[patch V3 06/14] x86: Select ARCH_MEMORY_ORDER_TOS

[Thomas Gleixner]

The generic unsafe_atomic_store_release_user() implementation does:

    if (!IS_ENABLED(CONFIG_ARCH_MEMORY_ORDER_TOS))
        smp_mb();
    unsafe_put_user();

As x86 implements Total Store Order (TOS) which means stores imply release,
select ARCH_MEMORY_ORDER_TOS to avoid the unnecessary smp_mb().

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxx>
Reviewed-by: André Almeida <andrealmeid@xxxxxxxxxx>
---
V3: Rename to TOS - Peter
V2: New patch
---
 arch/x86/Kconfig |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -114,6 +114,7 @@ config X86
 	select ARCH_HAS_ZONE_DMA_SET if EXPERT
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select ARCH_HAVE_EXTRA_ELF_NOTES
+	select ARCH_MEMORY_ORDER_TOS
 	select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE
 	select ARCH_MIGHT_HAVE_ACPI_PDC		if ACPI
 	select ARCH_MIGHT_HAVE_PC_PARPORT